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Phenotypes associated with this allele
Allele Symbol
Allele Name
Allele ID 		Spentm2.1Hon
targeted mutation 2.1, Tasuku Honjo
MGI:3710413
Summary 4 genotypes
Jump to Allelic Composition Genetic Background Genotype ID
cn1
 		Cd19tm1(cre)Cgn/Cd19+
Spentm2.1Hon/Spentm2.1Hon 		involves: 129P2/OlaHsd * C57BL/6 * CBA MGI:3710553
cn2
 		Cd19tm1(cre)Cgn/Cd19+
Rbpjtm1Hon/Rbpjtm1Hon
Spentm2.1Hon/Spentm2.1Hon 		involves: 129P2/OlaHsd * C57BL/6 * CBA MGI:3710554
cn3
 		Spentm2.1Hon/Spentm2.1Hon
Tg(Nes-cre)1Kag/? 		involves: C57BL/6 * CBA MGI:3710557
cn4
 		Spentm2.1Hon/Spentm2.1Hon
Tg(Camk2a-cre)10Kmik/? 		involves: C57BL/6 * CBA MGI:3710558


Genotype
MGI:3710553
cn1
Allelic
Composition		 Cd19tm1(cre)Cgn/Cd19+
Spentm2.1Hon/Spentm2.1Hon
Genetic
Background		 involves: 129P2/OlaHsd * C57BL/6 * CBA
Find Mice Using the International Mouse Strain Resource (IMSR)
Mouse lines carrying:
Cd19tm1(cre)Cgn mutation (12 available); any Cd19 mutation (57 available)
Spentm2.1Hon mutation (3 available); any Spen mutation (137 available)
♀ phenotype observed in females
♂ phenotype observed in males
N normal phenotype
immune system
decreased follicular B cell number ( J:121523 )
• decreased numbers of follicular B cells in spleen
increased marginal zone B cell number ( J:121523 )
• increased numbers of marginal zone B cells in spleen

hematopoietic system
decreased follicular B cell number ( J:121523 )
• decreased numbers of follicular B cells in spleen
increased marginal zone B cell number ( J:121523 )
• increased numbers of marginal zone B cells in spleen




Genotype
MGI:3710554
cn2
Allelic
Composition		 Cd19tm1(cre)Cgn/Cd19+
Rbpjtm1Hon/Rbpjtm1Hon
Spentm2.1Hon/Spentm2.1Hon
Genetic
Background		 involves: 129P2/OlaHsd * C57BL/6 * CBA
Find Mice Using the International Mouse Strain Resource (IMSR)
Mouse lines carrying:
Cd19tm1(cre)Cgn mutation (12 available); any Cd19 mutation (57 available)
Rbpjtm1Hon mutation (2 available); any Rbpj mutation (191 available)
Spentm2.1Hon mutation (3 available); any Spen mutation (137 available)
♀ phenotype observed in females
♂ phenotype observed in males
N normal phenotype
immune system
decreased marginal zone B cell number ( J:121523 )
• severely decreased numbers of marginal zone B cells in spleen
increased follicular B cell number ( J:121523 )
• increased numbers of follicular B cells in spleen

hematopoietic system
decreased marginal zone B cell number ( J:121523 )
• severely decreased numbers of marginal zone B cells in spleen
increased follicular B cell number ( J:121523 )
• increased numbers of follicular B cells in spleen




Genotype
MGI:3710557
cn3
Allelic
Composition		 Spentm2.1Hon/Spentm2.1Hon
Tg(Nes-cre)1Kag/?
Genetic
Background		 involves: C57BL/6 * CBA
Find Mice Using the International Mouse Strain Resource (IMSR)
Mouse lines carrying:
Spentm2.1Hon mutation (3 available); any Spen mutation (137 available)
Tg(Nes-cre)1Kag mutation (0 available)
♀ phenotype observed in females
♂ phenotype observed in males
N normal phenotype
mortality/aging
premature death ( J:121523 )
• increased mortality before 10 weeks of age

growth/size/body
postnatal growth retardation ( J:121523 )
• although normal at birth, mice are growth retarded at 3 weeks of age

nervous system
small hippocampus ( J:121523 )
• reduced in size
thin cerebral cortex ( J:121523 )
• severe reductions in the thickness of the cerebral cortex




Genotype
MGI:3710558
cn4
Allelic
Composition		 Spentm2.1Hon/Spentm2.1Hon
Tg(Camk2a-cre)10Kmik/?
Genetic
Background		 involves: C57BL/6 * CBA
Find Mice Using the International Mouse Strain Resource (IMSR)
Mouse lines carrying:
Spentm2.1Hon mutation (3 available); any Spen mutation (137 available)
Tg(Camk2a-cre)10Kmik mutation (1 available)
♀ phenotype observed in females
♂ phenotype observed in males
N normal phenotype
nervous system
abnormal brain size ( J:121523 )
• brain hypoplasia by 8 weeks of age

behavior/neurological
abnormal learning/memory/conditioning ( J:121523 )
• reduced freezing response to foot shock during training
abnormal contextual conditioning behavior ( J:121523 )
• reduced freezing response
abnormal cued conditioning behavior ( J:121523 )
• reduced freezing response




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Mouse Genome Database (MGD), Gene Expression Database (GXD), Mouse Models of Human Cancer database (MMHCdb) (formerly Mouse Tumor Biology (MTB)), Gene Ontology (GO)
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Send questions and comments to User Support. 		last database update
10/07/2025
MGI 6.24 		The Jackson Laboratory